Artificial limb



A. PRlNGLE AND T. S. KlRK.

ARTiFlClAL LIMB. APPLICATION FILED NOV-16,1920.

Patented July 19, 1921..

I i/ fi o/"rm 2/5.

ALEXANDER PRINGLE Ann THOMAS SINCLAIR KIRK, or BELFAST, IR N ARTIFICIAL LIME.

Original application filed August 6, 1920, Serial No. 401,606.

Specification of Letters Patent.

Patented July in, rear. Divided and this application filed November 16, 1920. Serial No. 424,365.

To al whom it may concemt:

Be it known that we, ALEXANDER PRINGLE and Triorras SINCLAIR KIRK, subjects of the King of Great Britain and Ireland, residing at Belfast, Ireland, have invented certain .neW and useful Improvements Relating to Artificial Limbs, of which the following is a specification.

This invention relates to artificial legs and joints therefor and is a subdivision of the pending patent application Serial No. 401,606, filed August 6th 1920.

According to the invention the leg com.- prises a plurality of lateral frames connected by oppositely disposed diagonal links while the joint comprises a pair of oppositely disposed toggles, or a plurality of such pairs, which are, or are adapted to be, pivotally connected with the leg. Locking means are provided in connection. with the toggles whereby the joint may be locked in different positions, such means comprising suit ably arranged teeth or indents on the links of one toggle and a coacting pin or equivalent at the junction of the links the other toggle.

In order that the invention may be clearly understood an explanatory drawing is hereunto appended, whereon Figures 1 and 2 are, respectively, side and back elevations of one form or embodiment of the invention and Fig. 3' is a section on the line 3--3, Fig. 2. As illustrated, the leg comprises lateral cross frames l connected by oppositely disposed diagonal links 5 which are riveted thereto so that a rigid structure is obtained, the whole being surrounded by a suitable casing 6. The foot 7 is connected with the lower frame 4: by oppositely disposed diagonal links 8 which are pivotally connected to both foot and frame so as to allow of relative movement therebetween. Spring cushionin (.lGVli'OS 9 may be provided in connection with the foot 7 and. adapted to (o-act with the lower frame t or other suitable part of the leg to absorb or cushion any shock due to impact of the foot with the ground.

The knee joint comprises pairs of. oppositely disposed toggles located, at opposite sides of the leg and pivotally connected with the upper and lower leg portions. Each pair consists of toggles 10 and 11, the former comprising segmental links 12 and 13 united by a common pivot pin 14 while the latter connecting same and comprises plain links 15, 16 mon pivot pin 17. Formed in the links 12, 13, about the pivot pin 14, are arcuate slots 18, 19 bounded, at their outer sides, by teeth 20, 21. The pivot pin 17 is so arranged that the extremities thereof are adapted to engage the indents between the teeth 20, 21 which may be moved into or out of register by movement of one or both of the links 12. 13 about the pivot pin 14.

In bending the leg at the knee the links 15, 16 are moved toward alinement and the pm 17 drawn out of engagement with the indentsbetween the teeth 20, 21. A tendency to bend the knee beyond the perpendicular in the wrong direction causes the links 15, 16 to move toward coincidence and move the pin 17 into engagement with the indents between the teeth 20, 21 and so lock the oint against movement in that directron. Tensioning of the knee joint causes the pins 14 and 17 to be moved toward one another and, consequently, the pin 17 to be disengaged from the teeth 20, 21, while compression of the joint, such as by the application of weight, causes the pins to be extended and the pin 17 to engage the teeth 20, 21. These movements, and resultant action of the knee joint, or components of a number of them, are utilized in walking, the arrangement being simple and automatic in action.

Having now fully described our invention what we claim and desire to secure by Letters Patent is 1- 1. In an artificial leg a plurality of transverse frames and oppositely disposed diagonal links rigidly connecting same. i

2. In an artificial leg a plurality of frames, oppositely disposed diagonal links a casing surrounding united by a comsaid frames and links.

In an artificial leg, :1 a pair of oppositely disposed toggles and teeth in'connection with the links of one toggle adapted to be engaged by the pivot of the, other toggle.

4t. Inan artificial leg, a joint comprising a pair of oppositely disposed toggles, in connection with the toothed segments links of one toggle and a projection on the pivot pin connecting the links of the other toggle adapted to engage the aforesaid toothed segments.

joint comprising a plurality 5. In an artificial leg, aljoint comprising pairs of oppositely disposed toggles having two common pivot pins and toothed'sectors in connection with one toggle of each pair adapted to be engaged by the pivot pin on which is mounted the other toggle of each 6. In an artificial leg, a joint comprising a plurality of frames, pivoted links connects ing said frames and means in connection with certain of said links ior engaging the pivot ofcertain other of said links.

7 In an artificial leg, a joint comprising of frames, pivoted links connecting-same, toothed segments in connection with'certain of said links and adapted to register with one another and means at the pivot of certain other of said links adapted to eiwage said segments.

8. 11 an artificial leg, a joint comprising a pair of oppositely disposed toggles one vof which is composed of segmental links,

toothed sectors on the segmental links and a projection on the pivot pin of the other toggle adapted to engage said toothed sectors. y

In testimony whereof we affix our signatures in presence of two witnesses.

ALEXANDER PRINGLE.

THOMAS SINCLAIR KIRK.

Witnesses:

ANDREW HAMILTON, HARRY WALTER ALLsoP. 

